Dialkyl-alpha, alpha&#39;-dicyano-2, 5-dialkoxy-p-benzenediacrylates



Patented Feb. 16, 1954 DIALKYL- a,a'-DICYANO-2,5 -DIALKOXY-p- BEN ZEN EDIACRYLATES Nichlas W. Solon en and David I. Randall, Easton, Pa., assignors to. General Aniline & Film Corporation, New York, N.]Y.,.a corporation of Delaware No Drawing, Application-Septemher4195L Serial No. 2455074.. 1

This: invention relates to dialkyl e dicyano- 2,5-dialkoxy-p-benzenediacrylates which are new dyestufis having brilliant colors and strong fluorescent properties.

It is known that a cyanoacetic ester can be condensed with a p-dialkylaminobenzaldehyde in the presence of alcohol and abasic condensingv agent to yield yellow to orange dyestuffs. Suchdyestufis are particularly valuable for dyeing cellulose acetate silks from aqueous suspensions or solutions but the dyes do not possess any fluorescent properties. The condensation of ethylcyanoacetate with terephthalaldehyde yields a product having mild fluorescent properties and little or no pigment value due to thelack of color strength.

It is an object of the, present invention to provide a new class of dyestuiTs which have a brilliant orange color of. stronglyfluorescent-properties.

Other objects and advantages' will appear hereinafter.

We have found that dyes having the'foregoing,

properties and characteristics are characterized by the following general formula:

N I CN wherein the Rs represent a lower alkyl group, e. g., methyl, ethyl, propyl, isopropyl, butyl, and the like.

The dyes are readily prepared by condensing one mole of 2,5-lower dialkoxyterephthalaldehyde with two moles of a cyanoacetic ester in the presence of alcohol in a small quantity of a basic condensing agent, such as pyridine. The condensation is readily carried out by first dissolving the 2,5-dialkoxyterephthalaldehyde in a sufiicient quantity of absolute ethanol to form a solution followed by the addition of the cyanoacetic ester and a small quantity of piperidine or pyridine as the condensing agent. The resulting solution is gradually brought up to reflux and maintained at that temperature for a period of one hour with efficient stirring. The reaction mixture is then cooled to room temperature and the product filtered off. The press-cake is then washed with an alcohol, such as methanol or ethanol, followed by washing with water and the washed product is finally dried in a vacuum desiccator.

The dyestufis characterized by the foregoing formula are particularly valuable in th pigment field. especially as Day-G colors due to their 4 Claims. (01. zen-Assistrong fluorescent properties in ultravioletlight. Both in the form: of varnish drawdowns (full shade) andv Beetle resin coatings, their daylight fluorescence is unusually strong. The dyestulfs hayethe. distinct advantage of possessing good fastness to light in the formof full shade varnish drawdowns. The most unusual featur of the dyes, however, is. their. distinctly bright shades. It isbelieved. that their brilliant color and strong- 1y fluorescent properties are due to the. presence of. thelower dialkoxy groups in, the 2'- and-5.- positions of the benzene nucleus.

As examples of suitable 2,5-lower dialkoxyterephthalaldehydes which may be. condensed with the cyanoacetic ester, the following are H1115!- trative:

2,5-dimethoxyterephthalaldehyde 2,5ediethoxyterephthalaldehyde 2,-5-dipropoxyterephthalaldehyde 2,5-diisopropoxyterephthalaldehyde- 2.5edibutoxyterephthalaldehyde 'As examples of suitable cyanoacetic esters which may be condensed withth 2,5.-lower di alkoxyterephthalaldehydes, the following may be mentioned:

Methylcyanoacetate Ethylcyanoacetate fi-Hydroxyethylcyanoacetate Propylcyanoacetate Isopropylcyanoacetate Butylcyanoacetate Sec. butylcyanoacetate EXAMPLE I (I) OH:

15 parts of 2,5-dimethoxyterephthalaldehyde were added to 238 parts of absolute ethanol followed by the addition of 32 parts of ethylcyanoacetate and 3.5 parts of piperidine. The resulting mixture was gradually brought up to reflux and maintained at that temperature for a period of 1 hour with efficient stirring. The reaction was then cooled to room temperature and the product filtered off. The press-cake was washed with 118 parts of methanol followed by washing with 3 water. The product was dried in a vacuum desiccator. The dyestufi is a brilliant orange of strongly fluorescent properties and possesses good fastness to light in the form of full shade varnish drawdowns.

EXAMPLE If. (I)C:Hi

CH:OOC-C=HC CH=C-COOCH| N l N OCIHE Example I was repeated with the exception that 15 parts of 2,5-dimethoxyterephthalaldehyde and 32 parts of ethyleyanoacetate were replaced by 21.5 parts of 2,5-dibutoxyterephthalaldehyde and 39.4 parts of isopropylcyanoacetate. The dried dyestuff is a very brilliant orange and possesses good fastness to light in the form of full shade varnish drawdowns.

While we have disclosed the preferred embodiments of our invention and the preferred modes of carrying the same into effect, it will be readily apparent to those skilled in this art that many variations may be made therein without departing from the spirit thereof. Accordingly, the scope of our invention is to be limited solely by the following claims.

4 We claim: 1. Dialkyla,a'- dicyano- 2,5- dialkoxypbenzenediacrylates characterized by the following general formula:

wherein the Rs represent a lower alkyl group.

2. Diethyl-a,a-dicyano- 2,5- dimethoxy-p-benzenediacrylate having the following formula:

CN N

3. Dimethyl-a,a'-dicyano-2,5- diethoxy-p-benzenediacrylate having the following formula:

4. Di-isopropyla,a'- dicyano- 2,5- dibutoxy-pbenzenediacrylate having the following formula:

NICHOLAS W. SOLONEN. DAVID I. RANDALL.

References Cited in the file of this patent 

1. DIALKYL- A,A''- DICYANO- 2,5- DIALKOXY- P- BENZENEDIACRYLATES CHARACTERIZED BY THE FOLLOWING GENERAL FORMULA: 